Widescan coils

[BarberBill]

Here's a question that wandered into my mind recently. I've read many times that the depth of an elliptical, widescan coil will be approx. equal to the width. IE, 6X10 elliptical would be around 6" etc. However, I got to wondering how that works if we're talkig about, for instance, a 9" Round widescan coil? Any comments??
BB

 

[MarkCZ]

So far in air test both my brother and I have seen very little difference in depth from one coil to another, be it Widescan or Concentric. The biggest thing that varied the depth was Gold Rings and Nickels, or items in that conductive range, not really the coil, even the size made very little difference.
But that was air testing, but it bad soil the DD should handle it better and give more depth than the Concentric.

Mark

 

[Neil]

Bill Ive used and still have/use a variety of widescans and it really depends on the coil and the detector its hooked up to. Ive got an 8" minelab tornado coil that actually measures 7.25" across(its a round coil) that I can dig coins with on the beach 12" down with a good set of headphones. Coiltek makes a 5X10 Joey elliptical widescan, hooked up to the same detector(Sov) and the depth is about the same or actually a little less.
Ive dug coins 10" down with my garrett at pro which has an 8" elliptical styled widescan on it, measures about 5" across the center but 8" long.
Ive only used two Tesoro widescans that met or exceeded their size. That was a 12X10 that I had hooked up to both a Vaquero and Tejon a few years back(coins 12" deep with it also) and both in the past and currently the 3X18 widescan which I was just using this past weekend and dug some coins 6" deep with it.
Ive found that for the same size in length, comparing an elliptical with a round coil, both being widescans, the round coil will get the better depth and by a few inches.
Widescans also vary a lot in how they separate, some are truly like windshield wipers in their coverage,they put down thin detection line that really allows for great separation but others have wider center detection lines.
One thing I really like about widescans is the coverage. Ive read this whole thing about how many inches of ground covered times depth equals so much ground and you can go by that but what I go by is at depth, at 7" what is your coil seeing or responding to? I mean at 7" down, compare a 9" concentric and a 9" widescan and you will see you can hit the 7" target on a larger percent of the widescan coil than you can a concentric. Generally concentrics have greatly reduced coverage at depth which is of no use to me hunting beaches.

 

[MarkCZ]

Here's a question that wandered into my mind recently. I've read many times that the depth of an elliptical, widescan coil will be approx. equal to the width. IE, 6X10 elliptical would be around 6" etc. However, I got to wondering how that works if we're talkig about, for instance, a 9" Round widescan coil? Any comments??
BB

Now I was talking about Tesoro's and the Widescan coils, others I don't think refers to their DD coils as "Widescan" so, on other brands of detectors it may me a different story. Me and my brother both were surprised to little difference the depth was with different size coil on our Tejon's.

Mark

 

[WV62]

Brother Mark is right on about the Tesoro's up to a point they do air test the same. Now on my F5 the 10" concentric air tested better than the 11" DD coil, but when I put them on my test garden the DD took the lead.

I think the coil width = to depth in the ground is a little flawed. The width on my 11" DD is about 7" and I can say around here it will do better than that. Could be that who ever come up with that rule of thumb, it may have been true in their soil.

Around here I will stick with the DD coil.

Ron in WV

 

[Neil]

Here's a question that wandered into my mind recently. I've read many times that the depth of an elliptical, widescan coil will be approx. equal to the width. IE, 6X10 elliptical would be around 6" etc. However, I got to wondering how that works if we're talkig about, for instance, a 9" Round widescan coil? Any comments??
BB

Now I was talking about Tesoro's and the Widescan coils, others I don't think refers to their DD coils as "Widescan" so, on other brands of detectors it may me a different story. Me and my brother both were surprised to little difference the depth was with different size coil on our Tejon's.

Mark

Hi Mark,
This is off the Tesoro home website under the coils link:

There are two main types of searchcoils currently on the market

 

[MarkCZ]

With our Tesoro testing so far it still comes out the same with the coils we've tested. Very little depth difference in our Tesoro's with any coil or shape of coil we've put on them, or to say I can't see a pattern in the width so far that changes anything about the depth.
5.75" Concentric, (round coil)
5.75" Widescan (round coil)
8"x 9" Concentric (elliptical)
10"x 12" Widescan (elliptical)
5.5"x 9.5" Widescan (elliptical)

But, "Neil" your right about his question! thanks for pointing that out to me.

 

[Neil]

I was saying the width of detection effects the separation not the depth. Did you ever use a T2 or F75? The difference between the detection width on them compared to say a Tesoro 7" is quite pronounced(both widescans). All of the SEF coils(that Ive used) also have that super tight windshield wiper type detection width that seperates better.

 

[MarkCZ]

I was saying the width of detection effects the separation not the depth. Did you ever use a T2 or F75? The difference between the detection width on them compared to say a Tesoro 7" is quite pronounced(both widescans). All of the SEF coils(that Ive used) also have that super tight windshield wiper type detection width that seperates better.

Yes, all the DD coils I have used has a more bar like field of detection, sort of like a disc shape field on edge. But, no I've never tried to compare the difference between the Tesoro's and the F75, although my Brother has both a Tejon and a F75.
I have noticed that my Omega and the 11" DD coil has a very narrow detection field, way more so than the 10" concentric elliptical.
On my Omega I've landed on using the 11" DD exclusively and this year I want to try the same thing with my Tejon, other than the DD's seem to have more of a problem with rusty bottle caps. For me and where I live the pros and weighs the cons, with better separation and better depth and with the Tejon it seems to help increase sensitivity to small gold jewelry items.

Mark

 

[WV62]

Here is a picture of a work sheet I done of all the coils we could round up for the Tesoro Tejon. Thought this may help to answer the question a little.

Ron in WV

 

[Larry (IL)]

That old formula is only a rule of thumb to compare concentric and elliptical concentric coils against each other. It was used before coil technology got specialized with the DD/SEF configurations now commonly used. The actual depth of ANY coil is very dependent on ground mineralization. The same coil might get 12 inches on white beach sand and air testing yet only 4 inches in magnetic mineralized ground.

As the saying goes........ your results may vary.

 

[knarfj]

That old formula is only a rule of thumb to compare concentric and elliptical concentric coils against each other. It was used before coil technology got specialized with the DD/SEF configurations now commonly used. The actual depth of ANY coil is very dependent on ground mineralization. The same coil might get 12 inches on white beach sand and air testing yet only 4 inches in magnetic mineralized ground.

As the saying goes........ your results may vary.